8x8 led matrix build using WS2811 led strip

I want to build the 8x8 matrix using WS2811 LED strip
I will cut it into 8led strips

My question is about the best way to connect it.
I will be powering it from external 5v power supply. I have 2A would this be enough to power 64 leds plus arduino.

I am plannint to connect this external power supply to gnd and vin pin of arduino. And also to the 5v and GND of the first 8led strip. and then with cable chain connect the other 7 8 led strips.

Would that work or do I have to connect 5v and ground to first strip and chain connect e.g next 3 strips and then continue with data wire to remaining 4 strips but connect those 4 strips directly to exernal 5v just like I did with first four.
Not sure If I am making myself clear so I drew two diagrams.

Also I have some doubts i 5v is enough to power arduino Nano via VIN pin. I thought it is 6v-12v required.


Do I need any resistors or capacitors

theoretically if you light them up all in full white (R,G,B at max) then you need 60mA per LED. 64 x 0,060 = 3,84A ➜ so not enough with 2A. if you limit to 40% brightness then you should be ok.

regarding the wiring, if it works with the 64 LEDs in one linear strip, cutting and soldering in a different way just to change the layout does not change anything to current flow (assuming good short wires). So you would not need anything extra than the normal setup

Thanks. What about the capacitor and resistors. Are they needed?

were they needed in the documentation you had for your strip ?

this is a good intro to the neopixel strips:

they state

When connecting NeoPixels to any LIVE power source or microcontroller, ALWAYS CONNECT GROUND (–) BEFORE ANYTHING ELSE. Conversely, disconnect ground last when separating.

When using a DC power supply, or an especially large battery, we recommend adding a large capacitor (1000 µF, 6.3V or higher) across the + and – terminals. This prevents the initial onrush of current from damaging the pixels. See the photo on the next page for an example.

Adding a ~470 ohm resistor between your microcontroller's data pin and the data input on the NeoPixels can help prevent spikes on the data line that can damage your first pixel. Please add one between your micro and NeoPixels! Our NeoPixel rings already have this resistor on there

Ok. Thanks Thats exactly what I needed:)

you can use their matrix library

Wrong! Do not use "Vin" (or the "barrel jack" of a UNO); it is generally quite useless (due to the limitations of the on-board regulator). 5 V goes to the "5V" or "Vcc" pin.

256 LEDs is quit a lot. Connect 5 V and ground together down each side of your array to distribute the power uniformly.

Would be a good idea to get a 5 A supply.

It’s an 8x8 matrix, so 64 Not 256?

Oh well. :roll_eyes: